A horizontal calibration method for a panoramic image or video, comprises steps of: receiving images or video frames of two circles after being imaged by two cameras having opposite photographing directions; acquiring a horizontal calibration matrix during photographing by means of a gyroscope; and mapping, according to the horizontal calibration matrix, the images or video frames of the two circles to a left hemispherical curved surface and a right hemispherical curved surface of a spherical panoramic mathematical model in a UV mapping manner, respectively, whereby the panoramic images or video frames mapped in the spherical panoramic mathematical model being horizontal; wherein the step of acquiring the horizontal calibration matrix during photographing by means of a gyroscope, further comprises steps of: during photographing, according to a gravity vector and a reference absolute horizontal gravity vector (0, 0, -1) of the gyroscope, acquiring a horizontal calibration quaternion, specifically: calculating the horizontal calibration quaternion q from v1 rotation to v2, as: ν 1 = x 1 y 1 z 1 ν 2 = ⌈ x 2 y 2 z 2 ⌉ ν 3 = ⌈ x 3 y 3 z 3 ⌉ dot = ν 1 • ν 2 = x 1 x 2 + y 1 y 2 + z 1 z 2 = ν 1 × ν 2 × cos angle an gle = a cos dot ∗ 180 / π ν 3 = ν 1 × ν 2 = x 1 y 1 z 1 × x 2 y 2 z 2 = y 1 z 2 − z 1 y 2 z 1 x 2 − x 1 z 2 x 1 y 2 − y 1 x 2 q = w x y z = cos angle / 180 ∗ π / 2 sin angle / 180 ∗ π / 2 ∗ x 3 sin angle / 180 ∗ π / 2 ∗ y 3 sin angle / 180 ∗ π / 2 ∗ z 3 where, v1 represents the gravity vector of the gyroscope, v2 represents the reference absolute horizontal gravity vector, angle represents a rotation angle about an axis, v3 represents a vector of multiplying matrix v1 by matrix v2; and converting the horizontal calibration quaternion to the horizontal calibration matrix specifically, converting the horizontal calibration quaternion to the horizontal calibration matrix M0 of 4 * 4: M 0 = 1.0 − 2.0 ∗ y 2 + z 2 2.0 ∗ xy + wz 2.0 ∗ xz − wy 0 2.0 ∗ xy − wz 1.0 − 2.0 ∗ x 2 + z 2 2.0 ∗ yz + wx 0 2.0 ∗ xz + wy 2.0 ∗ yz − wx 1.0 − 2.0 ∗ x 2 + y 2 0 0 0 0 1. receiving images or video frames of two circles after being imaged by two cameras having opposite photographing directions; acquiring a horizontal calibration matrix during photographing by means of a gyroscope; and mapping, according to the horizontal calibration matrix, the images or video frames of the two circles to a left hemispherical curved surface and a right hemispherical curved surface of a spherical panoramic mathematical model in a UV mapping manner, respectively, whereby the panoramic images or video frames mapped in the spherical panoramic mathematical model being horizontal; wherein the step of acquiring the horizontal calibration matrix during photographing by means of a gyroscope, further comprises steps of: during photographing, according to a gravity vector and a reference absolute horizontal gravity vector (0, 0, -1) of the gyroscope, acquiring a horizontal calibration quaternion, specifically: calculating the horizontal calibration quaternion q from v1 rotation to v2, as: ν 1 = x 1 y 1 z 1 ν 2 = ⌈ x 2 y 2 z 2 ⌉ ν 3 = ⌈ x 3 y 3 z 3 ⌉ dot = ν 1 • ν 2 = x 1 x 2 + y 1 y 2 + z 1 z 2 = ν 1 × ν 2 × cos angle an gle = a cos dot ∗ 180 / π ν 3 = ν 1 × ν 2 = x 1 y 1 z 1 × x 2 y 2 z 2 = y 1 z 2 − z 1 y 2 z 1 x 2 − x 1 z 2 x 1 y 2 − y 1 x 2 q = w x y z = cos angle / 180 ∗ π / 2 sin angle / 180 ∗ π / 2 ∗ x 3 sin angle / 180 ∗ π / 2 ∗ y 3 sin angle / 180 ∗ π / 2 ∗ z 3 where, v1 represents the gravity vector of the gyroscope, v2 represents the reference absolute horizontal gravity vector, angle represents a rotation angle about an axis, v3 represents a vector of multiplying matrix v1 by matrix v2; and converting the horizontal calibration quaternion to the horizontal calibration matrix specifically, converting the horizontal calibration quaternion to the horizontal calibration matrix M0 of 4 * 4: M 0 = 1.0 − 2.0 ∗ y 2 + z 2 2.0 ∗ xy + wz 2.0 ∗ xz − wy 0 2.0 ∗ xy − wz 1.0 − 2.0 ∗ x 2 + z 2 2.0 ∗ yz + wx 0 2.0 ∗ xz + wy 2.0 ∗ yz − wx 1.0 − 2.0 ∗ x 2 + y 2 0 0 0 0 1. calculating the horizontal calibration quaternion q from v1 rotation to v2, as: ν 1 = x 1 y 1 z 1 ν 2 = ⌈ x 2 y 2 z 2 ⌉ ν 3 = ⌈ x 3 y 3 z 3 ⌉ dot = ν 1 • ν 2 = x 1 x 2 + y 1 y 2 + z 1 z 2 = ν 1 × ν 2 × cos angle an gle = a cos dot ∗ 180 / π ν 3 = ν 1 × ν 2 = x 1 y 1 z 1 × x 2 y 2 z 2 = y 1 z 2 − z 1 y 2 z 1 x 2 − x 1 z 2 x 1 y 2 − y 1 x 2 q = w x y z = cos angle / 180 ∗ π / 2 sin angle / 180 ∗ π / 2 ∗ x 3 sin angle / 180 ∗ π / 2 ∗ y 3 sin angle / 180 ∗ π / 2 ∗ z 3 where, v1 represents the gravity vector of the gyroscope, v2 represents the reference absolute horizontal gravity vector, angle represents a rotation angle about an axis, v3 represents a vector of multiplying matrix v1 by matrix v2; and converting the horizontal calibration quaternion to the horizontal calibration matrix specifically, converting the horizontal calibration quaternion to the horizontal calibration matrix M0 of 4 * 4: M 0 = 1.0 − 2.0 ∗ y 2 + z 2 2.0 ∗ xy + wz 2.0 ∗ xz − wy 0 2.0 ∗ xy − wz 1.0 − 2.0 ∗ x 2 + z 2 2.0 ∗ yz + wx 0 2.0 ∗ xz + wy 2.0 ∗ yz − wx 1.0 − 2.0 ∗ x 2 + y 2 0 0 0 0 1.