The　design　and　implementation　of　map　projection　and　coordinate　conversion　software　package　is　put　forward　in　this　paper.　This　software　package　is　designed　with　strategy　design　pattern　and　implemented　with　standard　C++.　Therefore,　it　can　be　used　in　multi-platforms　and　is　also　easier　to　be　developed　further　and　maintained.　The　software　package　has　already　been　employed　in　Geography　Information　System　(GIS)　we　self-developed　successfully.