This paper investigates the original book of Shuowenjiezi cited in Pak Sonsu(Choson dynasty)`s Shuowenjieziyizheng, by comparing it with two versions of Shuowenjiezi, Shuowenjiezi Zhenben(published in 1773) and Sun Xingyan version(published in 1809). First of all, by comparing Shuowenjieziyizheng with Shuowenjiezi Zhenben, there are 193 discrepancies between them. And then by comparing Shuowenjieziyizheng with Sun Xingyan version, there are 269 discrepancies between them. These discrepancies are mostly due to wrong transcription and a little intentional editing of Pak Sonsu. However, there are some discrepancies that the cause of difference can not be analyzed . And in conclusion, the original version of Shuowenjiezi cited in Pak Sonsu(Choson dynasty)`s Shuowenjieziyizheng might be Shuowenjiezi Zhenben. Pak Sonsu referred to the other version of Shuowenjiezi, such as Xu Kai version and Kangxizidian to proofread shuowenjiezi and published Shuowenjieziyizheng, the only annotated book of Shuowenjiezi in Choson dynasty.