By using the definition and properties of Smarandache function S(n),Smarandache LCM function SL(n)and generalized Euler function φ2(n),the solvability problems of arithmetic function equations S(SL(n23))=kφ2[n(3n-1)/2]related to pentagon number are studied,in which k∈Z+(Z+is a set of positive integers).The results are as follows:all positive integer solutions of the arithmetic function equations S(SL(n23)=kφ2[n(3n-1)/2]are(k,n)=(13,2),(2,12),(1,27).