The traction and braking calculation and kinematics related theories were used in the study of the electric multiple units(EMUs) braking calculation method. According to the deceleration characteristic of the EMUs braking system，the error of the approximate braking calculation was analyzed. The EMUs calculation method was proposed based on target deceleration，unit basic resistance，gradient resistance, and other related parameters. This method is proved correct in comparison with the system performance type test data of CRH6A EMUs. The result shows that the calculated braking time and braking distance are consistent with the test result, which is effective to support the design and development of EMUs.