Investigation of isotope shift(IS) of optical transition is a very important method to obtain the nuclear parameters of an atom. The previous reports on investigation of isotope shifts of Hg were principally focused on the strong transitions, such as 6~1S—6~3P(2537) and 6~3P—7~3S(5461). And in the analysis of the isotope shift, the contribution of p electron was completely ignored due to the contribution of s electron being greatly larger than that ofp electron. These led to the ignorance of the information on p electron.