β-form　propylene-ethylene　random　copolymer　(PPR)　and　high　melt　flow　rate　(MFR)　β-PPR　were　prepared　by　the　addition　of　rare　earth　β　nucleating　agent　and　peroxide　into　PPR.　Effect　of　MFR　on　crystallization　properties　of　β-PPR　was　studied　by　means　of　differential　scanning　calorimetry　(DSC)　and　X-ray　diffraction　(XRD).　It　was　found　that　the　introduction　of　peroxide　decreased　the　content　of　β　crystal.　PPR,　β-PPR　and　high　MFR　β-PPR　were　annealed　at　80°C　to　120°C　for　1　h.　The　results　show　that　with　the　increase　of　annealing　temperature,　the　crystallinity　of　pure　PPR　increases,　while　the　crystallinity　of　β-PPR　and　high　MFR　β-PPR　increase　first　and　then　decrease.　The　content　of　β　crystal　decreases　with　annealing　temperature.