A nuclear mass formula based on the macroscopic microscopic approach is proposed,in which the num-ber of model parameters is reduced compared with other macroscopic microscopic models.The root mean square(RMS) deviation with respect to 2314 training sets (measured nuclear masses) is reduced to 0.447 MeV,and the cal-culated value of each nucleus is no more than 0.8％ different from the experimental value.The single and two nucle-on separation energies and the shell gaps are calculated to test the model.The shell corrections and double magic number of superheavy nuclei are also analyzed.