In order to study the expansion characteristics of laser-induced discharge plasma (LDP), a set of extreme ultraviolet source for tin target discharge plasma based on pulsed CO2 laser was established. The plume was photographed by intensified charge-coupled device. 1-D vacuum arc model was used to explain the experimental results. The time-resolved plume images under different conditions were obtained by changing the discharge voltage and laser energy. The results show that, under the condition of 140mJ laser energy and 10kV discharge voltage, a stable discharge plasma was obtained. There is a corresponding relationship between the plume morphology and the current. It has undergone different stages of formation, expansion, contraction, re-expansion and dissipation. Discharge voltage and induced laser energy have effects on plume size, stability and formation time. This study is helpful to improve the stability of LDP source and the output power of extreme ultraviolet light.