Abstract: Carbon nanotubes were prepared by catalytic decomposition of benzene using floating transition method with ferrocene as catalyst.The carbon nanotubes were straight with diameter 40-100 nm and length 50-1 000 μm.Co-P nanoparticles were deposited on the carbon nanotubes by electroless process after pretreatment.The Co-P/carbon nanotubes were characterized by TEM,XRD and magnetometer.The results show that the structure of particles was sosoloid of phosphorus dissolved in microcrystalline cobalt matrix with the size of 15-40 nm.The coercive force of carbon nanotubes coated with Co-P was very high,reached to 1.332×106 A·m-1.After heat-treatment at 400 ℃,the new phase of Co2P was formed.Correspondingly,the coercive force decreased and the magnetic susceptibility increased respectively.