The　leachate　collection　system　(LCS)　is　an　important　component　of　the　barrier　system　of　landfills.　LCS　in　China　is　subjected　to　serious　clogging　due　to　the　more　degradable　organics　and　water　in　the　municipal　solid　wastes　(MSWs).　To　evaluate　the　service　life　of　LCS,　a　reactive　transport　model　is　developed　to　simulate　the　biogeochemical　clogging　in　LCS.　The　hydrolysis　reactions　of　degradable　components　and　the　kinetic　calcium　leaching　process　are　taken　into　account　to　calculate　the　generation　of　VFAs　and　Ca2+　in　MSW.　The　ionization　equilibrium　of　volatile　fatty　acids　(VFAs),　dissolution　equilibrium　of　calcium　carbonate,　and　the　kinetic　biodegradation　reactions　of　VFAs　are　considered　to　simulate　the　pH　variation,　calcium　carbonate　precipitation,　and　biofilm　growth　during　clogging.　By　comparing　with　the　laboratory　experiment　data,　the　proposed　numerical　model　shows　the　ability　to　accurately　predict　the　decrease　of　the　porosity　in　LCS.　Parameter　analysis　indicates　that　the　decrease　of　the　mass　fraction　of　degradable　components　in　MSW,　leachate　irrigation　rate,　and　calcium　ion　leaching　rate　can　significantly　extend　the　service　life　of　LCS.　The　proposed　reactive　transport　model　can　be　the　methodological　support　for　the　design　and　service　life　prediction　of　leachate　collection　systems　in　landfills.