Indonesia was the big fifth smartphone user in the world, smartphone user always increase signed by the increasing internet user. This research was conducting to know the users necessary to buy smartphone based on their characteristic. Forward chaining method was using rule base and "if then" principle, which is provide convenience to search. This research was using three criterias and three costs range. The three criterias was consisted by hobby, job and social networking. Each of criteria has four questions that users have to answer. The forward chaining method was implemented to the system by PHP programming language and database MySql. The test was resulting about 21 matching data which was conducting the test by the rule base system implementation. These 21 data was matching by the rule base and give the accuracy about 100%.

Keywords : Forward chaining, Rule base, Smartphone.