A method for obtaining evidences for illegal parking of a vehicle, wherein, a correspondence relationship between shooting positioning parameters of a first camera and a second camera is preset, the method comprises following steps: taking a first photo of an illegally parked vehicle using the first camera after detecting this vehicle by the first camera and obtaining a current first shooting positioning parameter of the first camera; calculating a second shooting positioning parameter of the second camera corresponding to the first shooting positioning parameter according to the correspondence relationship, and controlling the second camera to take a second photo with the second shooting positioning parameter, wherein the first photo is a photo of a vehicle head and the second photo is a photo of a vehicle rear, or the first photo is a photo of a vehicle rear and the second photo is a photo of a vehicle head; determining whether the vehicle for which the first photo is taken and the vehicle for which the second photo is taken are the same one by an image analysis technique; and if the vehicle for which the first photo is taken and the vehicle for which the second photo is taken are the same one, storing the first photo and the second photo as evidences for illegal parking; the correspondence relationship between the shooting positioning parameters of the first camera and the second camera is as follows: h × sin T tan P − h × cos T tan P 1 0 h × cos T tan P h × sin T tan P 0 1 α cos θ α sin θ a b = h ′ × sin T ′ tan P ′ h ′ × cos T ′ tan P ′, wherein h represents height of the first camera from ground, T represents pitch angel of the first camera, P represents horizontal rotational angle of the first camera, h ' represents height of the second camera from ground, T' represents pitch angle of the second camera, P ' represents horizontal rotational angle of the second camera, a, b, α and θ are determined by the following equation: x 1 − y 1 1 0 y 1 x 1 0 1 x 2 − y 2 1 0 y 2 x 2 0 1 x 3 − y 3 1 0 y 3 x 3 0 1 ⋮ ⋮ ⋮ ⋮ α cos θ α sin θ a b = x 1 ′ y 1 ′ x 2 ′ y 2 ′ x 3 ′ y 3 ′ ⋮, wherein ( x 1, y 1), ( x 2, y 2), and ( x 3, y 3) are three given coordinates in a three-dimensional rectangular coordinate system established by taking a projection of the first camera on the ground as an origin, ( x 1 ', y 1 '), ( x 2 ', y 2 '), and ( x 3 ', y 3 ') are three given coordinates in a three-dimensional rectangular coordinate system established by taking a projection of the second camera on the ground as an origin, the relationship between the coordinates and the shooting positioning parameters of a corresponding camera comprises: x = h × sin T tan P, y = h × cos T tan P, x ′ = h ′ × sin T ′ tan P ′, y ′ = h ′ × cos T ′ tan P ′. taking a first photo of an illegally parked vehicle using the first camera after detecting this vehicle by the first camera and obtaining a current first shooting positioning parameter of the first camera; calculating a second shooting positioning parameter of the second camera corresponding to the first shooting positioning parameter according to the correspondence relationship, and controlling the second camera to take a second photo with the second shooting positioning parameter, wherein the first photo is a photo of a vehicle head and the second photo is a photo of a vehicle rear, or the first photo is a photo of a vehicle rear and the second photo is a photo of a vehicle head; determining whether the vehicle for which the first photo is taken and the vehicle for which the second photo is taken are the same one by an image analysis technique; and if the vehicle for which the first photo is taken and the vehicle for which the second photo is taken are the same one, storing the first photo and the second photo as evidences for illegal parking; the correspondence relationship between the shooting positioning parameters of the first camera and the second camera is as follows: h × sin T tan P − h × cos T tan P 1 0 h × cos T tan P h × sin T tan P 0 1 α cos θ α sin θ a b = h ′ × sin T ′ tan P ′ h ′ × cos T ′ tan P ′, wherein h represents height of the first camera from ground, T represents pitch angel of the first camera, P represents horizontal rotational angle of the first camera, h ' represents height of the second camera from ground, T' represents pitch angle of the second camera, P ' represents horizontal rotational angle of the second camera, a, b, α and θ are determined by the following equation: x 1 − y 1 1 0 y 1 x 1 0 1 x 2 − y 2 1 0 y 2 x 2 0 1 x 3 − y 3 1 0 y 3 x 3 0 1 ⋮ ⋮ ⋮ ⋮ α cos θ α sin θ a b = x 1 ′ y 1 ′ x 2 ′ y 2 ′ x 3 ′ y 3 ′ ⋮, wherein ( x 1, y 1), ( x 2, y 2), and ( x 3, y 3) are three given coordinates in a three-dimensional rectangular coordinate system established by taking a projection of the first camera on the ground as an origin, ( x 1 ', y 1 '), ( x 2 ', y 2 '), and ( x 3 ', y 3 ') are three given coordinates in a three-dimensional rectangular coordinate system established by taking a projection of the second camera on the ground as an origin, the relationship between the coordinates and the shooting positioning parameters of a corresponding camera comprises: x = h × sin T tan P, y = h × cos T tan P, x ′ = h ′ × sin T ′ tan P ′, y ′ = h ′ × cos T ′ tan P ′.