Different from traditional cameras, light field camera sets a lenslet array between the main lens and the sensor at a specific position, which makes it possible to record the light intensity and the direction of light rays at the same time. In order to reconstruct the object-side light field, the reconstruction algorithm of the focal planes based on the light field camera was studied. Focal stack and projection slice theorem used in the algorithm was researched. Firstly, parameterized 4D light field definition and the working principle of light field camera were analyzed. Secondly, the depth reconstruction model of the camera was established and research the application of the projection slice theorem in getting the focal planes and then Derived the expression of the different focal planes images. Finally, according to the different focal planes images, the computational reconstruction algorithm was studied to realize the reverse reconstruction of the object-side light field. A micro light field camera was built contains lenslet array, collected the original light field, reconstructed the object light field by the method in this paper.The results show that the light field collected by light field camera can be filtered reverse reconstruction of the method proposed in this paper, the depth and the surface of object can be further reconstruction via the light field data. The focal planes images acquisition algorithm in this paper saves more than 30% time compared with other algorithms, and the Peak Signal to Noise Ratio of each focal plane image is between 25-30 dB, which meets the requirements of high precision, stability, reliability and fast speed of light field reconstruction.