Aiming at issue that most heterogeneous network selection algorithms fail to consider network load

an algorithm based on access network discovery and selection function（ ANDSF） is proposed to realize wireless heterogeneous network selection. Optimize and upgrade the original ANDSF architecture

so that it can get dynamic information of network; based on this architecture

combining business characteristics and network characteristics

analytic hierarchy process（ AHP） and cost function algorithm are used to select the most appropriate network for each type of service. Simulation results show that this algorithm can increase the access success rate about 15 %and reduce the access time delay about 50 ms. Meanwhile this algorithm can balance network load to a certain extent

and it is conducive to development of four network synergies.