Monitoring　operating　vehicles＇　fuel　consumption　and　emissions　is　necessity　for　evaluating　fuel　saving　and　emissions　reduction.　Taxis　are　one　of　the　key　objects　needed　energy　consumption　monitoring　in　passenger　transport　system.　However,　the　traditional　data　collection　methods　for　vehicle　fuel　consumption　and　emissions　had　high　cost　and　inconvenient　maintenance.　This　study　aims　at　proposing　an　approach　to　estimate　taxi　fuel　consumption　and　emissions　based　on　the　global　position　system　(GPS)　trajectory　data.　The　bench　test　experiment　was　first　conducted　with　three　different　driving　cycles:　cruising,　acceleration　and　deceleration,　and　the　composite　driving　cycle　including　these　two.　Then,　models　to　calculate　fuel　consumption　and　emission　based　on　the　driving　trajectory　reconstruction　were　proposed.　Therefore,　the　taxis＇　fuel　consumption　and　emissions　could　be　got　through　GPS　trajectory　data　corresponding　to　these　three　driving　cycles.　The　model　accuracy　were　verified　that　fuel　consumption　(92%)　and　CO2　emission　(95%)　fit　the　measurements　much　better　than　CO,　NOx,　and　HC　emission　models　(60%-70%).　Furthermore,　taking　fuel　consumption　per　100km　as　dependent　variable,　the　relative　errors　between　the　model＇s　outputs　and　field　measurements　were　1.9%　in　urban　areas　and　11.2%　in　comprehensive　operating　conditions　(i.e.　both　urban　and　suburb　areas).