Pre-Amplifier(PA) system of large laser prototype device is operated by five computers and one server，which control two hundreds types of equipments. Software adopts distributed configuration based on Common Object Request Broker Architecture(CORBA)，which comprises five sets of program deployed in different fields. Status data is transmitted by combining asynchronous and synchronous modes. User exclusive control is achieved by reservations. Two proprietary key algorithms including energy self-poise and picture amalgamation are studied. The control software can realize magnification in advance and automatic adjustment of energy for 8 laser beams.