Laminaria (Saccharina) is one of the economic important seaweeds. Through sequence analysis of 4 099 ESTs from Laminaria (971 were generated from our own cDNA laboratories and 3 128 were downloaded from updated EST databases) with SSRIT software, two hundred and fifty-four SSRs in 206 ESTs were found. From the 254 SSRs, sixty-three SSR primer-pairs were designed. In order to test their practicability, the 63 primer-pairs were tested in commonly used SSR reaction conditions using 12 Laminara DNA samples as templates. The results show that 23 SSR primer-pairs gave good amplification patterns on most (more than 80％) of the 12 Laminara DNA templates. Genetic diversity study of 12 Laminaria lines, which were widely used in breeding and economic cultivation in China, was performed based on the obtained SSR data.