In order to acquire the solid-fluid two phase flow centrifugal pump’s slurry head according with the fact, the solid phase effect coefficient must be calculated precisely. By analysising the acting forces on the solid particle, its moving differential equation was established. And the calculating formula of the solid phase effect coefficient was deduced based on the equation. For the sake of verifying its validity, a test of contrast and comparison on the calculating slurry heads by some ways was carried out. The results shows that the relative error values of the slurry head calculated are less than 2.00% with a small and stably error band. The method has the advantage of simple calculating process, high accuracy, low randomness and good practicability.