A pressure resistant basic shell consists of a can seaming portion, a countersink portion, a ferrule arc portion, an upward extension portion of ferrule and a center panel from periphery to center in the cross section; the countersink portion consists of a first straight portion, a fourth arc portion and a fifth arc portion, and the first end of first straight portion is connected with the corresponding end of seaming portion, and its second end is connected with the first end of fourth arc portion and the first straight portion is connected with the fourth arc portion in a tangent way; the second end of fourth arc portion is connected with the first end of fifth arc portion and the fourth arc portion and fifth arc portion are connected in an externally tangent way; wherein: the countersink portion also consists of a sixth arc portion and a second straight portion, and the second end of the fifth arc portion is connected with the first end of the sixth arc portion and the fifth arc portion and the sixth arc portion are connected in an internally tangent way; the second end of the sixth arc portion is connected with the first end of the second straight portion, and the sixth arc portion and the second straight portion are connected in a tangent way; the second end of the second straight portion is connected with the first end of the ferrule arc section and the second straight portion and the ferrule arc section are connected in a tangent way; The radius of the fifth arc portion is greater than or equal to 0.25mm and less than or equal to 2.5mm; The radius of the ferrule arc portion is greater than or equal to 0.25mm and less than or equal to 0.8mm; The junction of second straight portion and ferrule arc portion is defined as the auxiliary point, and the straight line vertical to the center panel through auxiliary point is defined as the auxiliary line A; the fifth arc portion, sixth arc portion and second straight portion are located at one side of the auxiliary line A and the ferrule arc section is located at the other side of the auxiliary line A; The direction of the auxiliary line A is defined as up and down direction, and the side of basic shell facing the outside of can is up and the side of basic shell facing the inside of the can is down; in the up and down direction, the center of the sixth arc portion is located below the upper surface of the center panel; The projection distance between the center of fourth arc portion and center of the fifth arc portion perpendicular to the auxiliary line A is greater than or equal to 0, and less than or equal to 0.5 times of the sum of the radius of the fourth arc portion and the radius of the fifth arc portion, characterized in that the radius of the sixth arc portion is greater than or equal to 2mm and less than or equal to 6.5mm; and the projection distance between the center of fourth arc portion and center of the fifth arc portion on the auxiliary line A is greater than or equal to 0.85 times of the sum of the radius of the fourth arc portion and the radius of the fifth arc portion, and less than or equal to the sum of the radius of the fourth arc portion and the radius of the fifth arc portion. the countersink portion also consists of a sixth arc portion and a second straight portion, and the second end of the fifth arc portion is connected with the first end of the sixth arc portion and the fifth arc portion and the sixth arc portion are connected in an internally tangent way; the second end of the sixth arc portion is connected with the first end of the second straight portion, and the sixth arc portion and the second straight portion are connected in a tangent way; the second end of the second straight portion is connected with the first end of the ferrule arc section and the second straight portion and the ferrule arc section are connected in a tangent way; The radius of the fifth arc portion is greater than or equal to 0.25mm and less than or equal to 2.5mm; The radius of the ferrule arc portion is greater than or equal to 0.25mm and less than or equal to 0.8mm; The junction of second straight portion and ferrule arc portion is defined as the auxiliary point, and the straight line vertical to the center panel through auxiliary point is defined as the auxiliary line A; the fifth arc portion, sixth arc portion and second straight portion are located at one side of the auxiliary line A and the ferrule arc section is located at the other side of the auxiliary line A; The direction of the auxiliary line A is defined as up and down direction, and the side of basic shell facing the outside of can is up and the side of basic shell facing the inside of the can is down; in the up and down direction, the center of the sixth arc portion is located below the upper surface of the center panel; The projection distance between the center of fourth arc portion and center of the fifth arc portion perpendicular to the auxiliary line A is greater than or equal to 0, and less than or equal to 0.5 times of the sum of the radius of the fourth arc portion and the radius of the fifth arc portion, characterized in that the radius of the sixth arc portion is greater than or equal to 2mm and less than or equal to 6.5mm; and the projection distance between the center of fourth arc portion and center of the fifth arc portion on the auxiliary line A is greater than or equal to 0.85 times of the sum of the radius of the fourth arc portion and the radius of the fifth arc portion, and less than or equal to the sum of the radius of the fourth arc portion and the radius of the fifth arc portion.