A total of 146 skin lesions were reported in 81 patients were used to evaluate the therapeutic effect of two high energy ultrapulsed CO₂ laser modes on seborrheic keratosis(SK),  which were randomly divided into A and B groups, with 73 sites in each group. Group A was treated with ultrapulsed mode, group B was treated with lattice laser mode. The efficacy, the degree of pain during treatment, the average number of treatments, the time of scab off, the duration of residual erythema retreat, and the adverse reactions were observed and compared between the two groups. After the treatment, the total cure rates of A and B were 100% and 95.89%, respectively, with no significant difference(P＞0.05). Comparison of the time of scab off, the duration of residual erythema retreat, and average number of treatments were statistically significant(P＜0.05). According to the rank sum test, the total adverse reactions of the two groups were statistically significant(Z=-3.129, P=0.002), but there was no significant difference in the further single adverse reaction(P＞0.05). It is found that the lattice mode and ultrapulsed mode of high energy ultrapulsed CO₂ laser are effective in treating SK, but it is safer than ultrapulsed mode with less trauma, faster healing, less adverse reactions.