In this paper， a three-dimensional magneto-optical trap based on a triangular diffraction grating is used to realize the cooling and trapping of 87Rb atoms. Firstly， the triangle diffraction grating is designed and fabricated independently， which can effectively suppress the zero-order optical efficiency under the condition of ensuring the reasonable diffraction efficiency and diffraction circular deviation， and its parameters meet the optical viscose balance conditions. Then a magneto-optical trap system is built based on the grating to carry out the atom trapping experiment. Under the reasonable parameter setting， the atomic trapping is successfully realized. It is estimated that the number of trapped atoms is in the order of 106. The success of the atom cooling trapping experiment based on the triangular diffraction grating is of great significance for the low power consumption and miniaturization of the three-dimensional magneto-optical trap， and is expected to be applied to the miniaturized precision measurement system of cold atoms.