We introduce symmetric form of discrete AKP system and show that all the bilinear ABS equations (except Q2 and Q4) can be obtained from the symmetric discrete AKP system by taking proper reductions and continuum limits. In addition, a new 8-point 3-dimensional lattice equation and a new 8-point 4-dimensional lattice equation are found. Both of them can be considered as extensions of the symmetric discrete AKP equation. (Joint with Kenichi Maruno and Jing Wang)