Thispaperstudiesaservice-inventorysystemwith(r，Q)replenishmentstrate-gy， considering modeling a service-inventory system with Erlang distribution leadtime as an M/M/ 1 queuing system.According to the stationary distribution of M/M/lqueue，the steady-state performance index for system profit control is derived， and the system average profit function is constructed.Aiming at maximizing system profit， we construct the optimal control model of system with satisfaction rate and service reliability level constraint ting，and seek for the optimal control strategy of service-inventory system.By proving the con-v exit y of profit function， the constrained optimization model is solved by genetic algorithm，and the unique maximum value of profit function and the optimal value of decision variables rand Q are obtained.The sensitivity of the system performance is analyzed by numerical ex-periments， which show that the optimal control strategy with Erlang distribution can im-prove the profit of the system.