【Objective】 To investigate how the reading cognitive abilities of the students in lower grades of primary school effected their mathematical ability. 【Methods】 Four hundred and eleven children who were from Grades one to two in one primary school in Wuhan were selected to participate in this project including six cognitive tests and an intelligence test. These six cognitive tests contained orthographic awareness test, phonological awareness test, morphological awareness test, rapid naming test, working memory test and voice short-term memory. And the analysis of stepwise regression method was used to study the relationship between the six cognitive abilities and children's mathematical ability. 【Results】 The results of regression analysis showed that phonological awareness was the main factor that could influence mathematical ability of children from grade one and grade two(Grade one: t=6.892,P<0.001; Grade two: t=2.491,P<0.05). 【Conclusions】 Phonological awareness has made great progress in the early grades and works as a main factor that could influence the development of mathematical ability of children in lower grade. The development of phonological awareness training may be effective in promoting children's mathematical ability.