MnSb2Te4 has the same crystal structure as MnBi2Te4. Whether it is an intrinsic antiferromagnetic TI, quantum anomalous Hall insulator or axion insulator like MnBi2Te4 [CHIN. PHYS. LETT. 36, (2019) 076801] has not been reported yet. The electronic structure and magnetism of MnSb2Te4 have been studied using first-principles calculations. The results show that the MnSb2Te4 is an antiferromagnetic semiconductor with a trivial energy gap ( similar to 0.132 eV). The band gap decreases to 0.057 eV under the tensile strain (1.03a(0), 1.03c(0)). The feature of Weyl semimetal could be presented in MnSb2Te4 with ferromagnetic phase under strain 3%. Thin films (011) are metals with antiferromagnetic order and also metals with ferromagnetic order. Thin film (111) with alternate of thick (1 septuple layer-7 septuple layers) is an intrinsic magnetic semiconductor with a trivial energy gap (0.002-0.344 eV) rather than an intrinsic quantum anomalous Hall insulator or axion insulator.