An angle correction method of a mobile robot in a working area, the method being characterised in that it comprises the following steps: obtaining a long straight line at an edge of an obstacle first found by the mobile robot, wherein the step of obtaining a long straight line at an edge of an obstacle first found by the mobile robot further includes: moving the mobile robot in a straight line until it encounters an obstacle and walks along an edge of the obstacle; obtaining a walking angle of the mobile robot multiple times within a predetermined time T0, using an angle sensor of the mobile robot; based on the multiple walking angles of the mobile robot, determining whether the multiple walking angle values are near A0 and all the differences between the multiple walking angles and A0 are less than a threshold D0, A0 being the average of the multiple walking angle values; and if yes, using the edge of the obstacle as the obtained long straight line; establishing a right-angle coordinate system based on the long straight line, wherein the step of establishing a right-angle coordinate system based on the long straight line further includes: establishing the right-angle coordinate system using the mobile robot as an origin, using an A0 direction of the long straight line as an X-axis positive direction, using a left vertical direction or right vertical direction perpendicular to the A0 direction of the long straight line a Y-axis positive direction; obtaining a walking angle of the mobile robot when it again detects a long straight line at an edge of an obstacle, using the angle sensor of the mobile robot; and based on the walking angle and the right-angle coordinate system, when an angle difference between the walking angle and an axis direction of the right-angle coordinate system is less than a preset value, correcting the walking angle to a corresponding axis direction. obtaining a long straight line at an edge of an obstacle first found by the mobile robot, wherein the step of obtaining a long straight line at an edge of an obstacle first found by the mobile robot further includes: moving the mobile robot in a straight line until it encounters an obstacle and walks along an edge of the obstacle; obtaining a walking angle of the mobile robot multiple times within a predetermined time T0, using an angle sensor of the mobile robot; based on the multiple walking angles of the mobile robot, determining whether the multiple walking angle values are near A0 and all the differences between the multiple walking angles and A0 are less than a threshold D0, A0 being the average of the multiple walking angle values; and if yes, using the edge of the obstacle as the obtained long straight line; moving the mobile robot in a straight line until it encounters an obstacle and walks along an edge of the obstacle; obtaining a walking angle of the mobile robot multiple times within a predetermined time T0, using an angle sensor of the mobile robot; based on the multiple walking angles of the mobile robot, determining whether the multiple walking angle values are near A0 and all the differences between the multiple walking angles and A0 are less than a threshold D0, A0 being the average of the multiple walking angle values; and if yes, using the edge of the obstacle as the obtained long straight line; establishing a right-angle coordinate system based on the long straight line, wherein the step of establishing a right-angle coordinate system based on the long straight line further includes: establishing the right-angle coordinate system using the mobile robot as an origin, using an A0 direction of the long straight line as an X-axis positive direction, using a left vertical direction or right vertical direction perpendicular to the A0 direction of the long straight line a Y-axis positive direction; obtaining a walking angle of the mobile robot when it again detects a long straight line at an edge of an obstacle, using the angle sensor of the mobile robot; and establishing the right-angle coordinate system using the mobile robot as an origin, using an A0 direction of the long straight line as an X-axis positive direction, using a left vertical direction or right vertical direction perpendicular to the A0 direction of the long straight line a Y-axis positive direction; obtaining a walking angle of the mobile robot when it again detects a long straight line at an edge of an obstacle, using the angle sensor of the mobile robot; and based on the walking angle and the right-angle coordinate system, when an angle difference between the walking angle and an axis direction of the right-angle coordinate system is less than a preset value, correcting the walking angle to a corresponding axis direction.