In　this　article,　the　analyzer　crystal　materials　of　series　of　esters　of　maleate　acid　had　been　synthesized.　And　finish　the　crystal　capability　experiments　of　these　crystals　in　the　different　polar　solvents.　The　result　was　that　the　polarity　of　solvent　makes　great　effort　to　the　appearance　of　the　crystal.　In　the　solvent　with　low　polarity　or　non-polarity　complete　crystal　of　series　of　esters　adapted　to　grow.　For　example,　in　the　benzene　solvent　the　crystal　could　show　good　crystal　capability　and　grow　excellent　crystal.　This　kind　of　good　crystal　amount　was　a　few,　the　shape　of　it　was　clear　and　its　surface　was　clean.　And　it　showed　better　crystal　capability　in　the　same　polarity　solvent　when　the　carbon　chain　was　shorter.　In　this　article　we　also　research　the　molecular　association　and　the　menstruum　adsorption　phenomenon　of　the　crystal　growing　section　in　the　solvent.