For resolving the high cost problem of multicast routing tree with just optimization the multicast routing cost or jus t optimization the wavelength number consumption,the longest path first (LPF) me thod and shortest path first (SPF) method based on the node light splitting constraint are respectively proposed to resolve the problem of joint optimizing multicast routi ng cost and wavelength consumption number in this paper.By checking whether the node on the minimal cost multicast tree violates the light splitting constraint,according to the wavelength tradeoff cost control factor,the longest path or shortest path on th e tree is selected first to realize the lowest multicast rauting cost and wavele ngth consumption.The longest pat h or new wavelength channel is selected to re-route the light splitting constraint node in the LPF algorithm with low total cost.However,the SPF algorithm selects the shortest path on the tree or new wavelength channel to re-route the light s plitting constraint node.The simulation results show that the proposed two algorithms can achieve the low routing cost and require a few w avelengths simultaneously for optical multicast routing.