To analyze the rotor dynamics of the multistage pump, it is necessary to calculate the dynamic coefficients of journal bearing. The derivatives of the Reynolds equation were transformed into difference forms. The Reynolds equation was solved by programming in the Matlab, then the distribution of the static pressure was obtained. The dimensionless pressure was determined by width-diameter ratio and eccentricity ratio. To get the eccentricity ratio, the bearing capacity was calculated by using Simpson’s integral formula. The eccentricity ratio was changed by using interpolation method until bearing capacity equal the reverse supporting force. The pressure of small disturbance was obtained by programming and calculating the dynamic coefficients. The width-diameter ratio and eccentricity ratio was set as 0.2 and 0.4 respectively. Compared the results of this algorithm with that of the short bearing approximation, it showed that this algorithm was reliable. The results showed that the cross-damping coefficients of one journal bearing were almost equal. The diagrams of the journal bearing’s pressure with small disturbance were drawn by Matlab.