Objective:To　investigate　mechanical　properties　of　polymethyl　methacrylate　(PMMA)　of　different　mixing　ratios.　Methods:At　25°C,　self-curing　denture　acrylic　and　liquid　dental　base　acrylic　resin　are　mixed　at　massvolume　ratios　of　1.5:1,　1:1,　1:1.25,　1:1.5,　1:1.75,　1:2　(g:ml)　respectively,　and　stirred　uniformly　with　a　stirring　speed　of　60　revolutions　per　minute.　A　mould　of　13mm　diameter　and　100mm　length　is　filled　with　the　mixture,　and　after　it　solidifies　it　is　polished.　The　size　of　the　model　is　accurate　to　0.01mm.　A　compression　test,　tensile　test　and　three-point　bending　test　are　conducted.　Results:The　difference　of　compressive　strength　between　groups　with　mixing　ratios　of　1.5:1　and　1:1　was　not　significant　(p=0.326).　However,　the　value　of　compressive　strength　of　each　of　the　first　two　groups　was　remarkably　higher　than　that　of　the　latter　four　groups　(p0.05),　but　the　value　of　each　groups　was　significantly　higher　than　in　the　latter　three　groups　(p