It　was　found　that　lanthanum　complex　of　cyclodextrin　derivative　(beta-CD-MAH-La)　was　a　highly　active　beta-nucleating　agent　for　isotactic　polypropylene　(iPP)　in　this　study.　The　influence　of　the　nucleating　agent　on　mechanical　properties　and　isothermal　and　nonisothermal　crystallization　behavior　of　iPP　has　been　investigated.　Results　showed　that　beta-CD-MAH-La　was　efficient　in　inducing　the　crystallization　of　iPP　into　beta-modification　(beta-iPP),　with　K　(beta)　value　of　0.84,　while　the　content　of　nucleating　agent　was　0.8　wt.%.　beta-iPP　could　form　extensively　in　the　isothermal　crystallization　temperature　range　from　110　A　degrees　C　to　140　A　degrees　C,　and　the　highest　amount　of　beta-crystal　content　was　formed　at　130　A　degrees　C.　Besides,　it　can　be　known　that　the　addition　of　beta-CD-MAH-La　can　obviously　facilitate　the　overall　crystallization　process　of　iPP.　Under　nonisothermal　condition,　beta-iPP　formed　at　the　suitable　cooling　rates,　ranging　from　5　A　degrees　C　to　10　A　degrees　C/min.　Furthermore,　the　nucleation　mechanism　of　beta-CD-MAH-La　for　iPP　was　correlated　to　the　special　configuration　of　beta-CD-MAH-La.