When calculating fractional-order differential dynamics systems numerically, there are difficulties of long-time memory storage by discretizing differential equation directly. In order to solve this problem, firstly, the differential equation was integrated once and then discretized. At the same time, a recurrence formula was given and its applicable conditions were discussed. Some common non-linear problems were calculated by this formula. The results of the above were consistent with those of other numerical methods. As whether there is chaotic motion in two-dimensional fraction-order continuous dynamics system is not concluded, this recurrence formula was used to study the two-dimensional continuous coupled Logistic model. It is found that there is only the limit cycle generated by the equilibrium point through Hopf bifurcation in this system without chaotic motion. Finally, the Lyapunov exponent criterion for the motion of two-dimensional fractional-order continuous Logistic system was given.