The enhanced effects of trihydroxymethylpropyl trimethylacrylate (TMPTA) on radiation crosslinking of PCL were investigated. It was revealed that the radiation cross-linking of PCL with additive of TMPTA wasn’t in correspondence with the classic Charlesby-Pinner equation, but followed Chen-Liu-Tang relation. The influence of Fe3O4 of two particle sizes and different contents on mechanical properties and shape memory effect of the composites were studied. The results showed that Fe3O4 with an extent of 5 to 30 phr did not cause the decline of the tensile strength of the composite sample. But with the increment of Fe3O4 content, the elongation at break of the composites decreased obviously and the recovery time was also reduced. Finally the interesting shape memory behavior of this composites induced by an ultrasonic alternating magnetic field was also tested. The results showed that with the increment of Fe3O4 content and magnetic field intensity, the composites exhibited a faster recovery rate and a higher efficiency of heat production.Cited