A　traffic　signal　control　algorithm　based　on　knowledge　of　traffic　engineers,　named　as　TCP　(Time　to　Change　Phase)　is　put　forward　in　this　paper.　The　TCP　algorithm　is　implemented　and　evaluated　through　microscopic　traffic　flow　simulation　software　TSIS　(Traffic　Simulation　Integrated　System).　The　measurements　of　effectiveness　(MOEs)　of　TCP,　fixed-time　and　actuated　control　are　compared　with　each　other.　The　simulation　results　show　that　TCP　algorithm　gets　better　MOEs.　Furthermore,　when　a　parameter　of　TCP　is　optimized　and　even　better　MOEs　are　gotten.　TCP　algorithm　is　simple　and　practical　and　also　has　some　characteristics　of　intelligence　and　robustness.　How　to　improve　TCP　algorithm　and　develop　traffic　signal　control　system　based　on　TCP　algorithm　are　also　outlined　as　future　work.