Branched InP nanowires with single crystalline and twinning structure have been successfully synthesized by solvothermal synthesis method using indium powder and white phosphorus as the reactants, cetyltrimethyl ammonium bromide (CTAB) as cationic surfactant and benzene as the solvent at 180°C. Results from XRD suggest that the synthesized sample can be indexed as sphalerite-structured, cubic phase InP with lattice constant of a=5.858Å. We have studied the influences of CTAB and reaction temperatures on the InP wire morphology. Results indicate that these two factors play the important roles in synthesizing the stable and desired patterned nanowires. On the basis of our findings, possible mechanisms are discussed.