LT codes can dramatically enhance the network throughput as a rateless code. By Analyze the application of LT codes, according to the characteristic of transmission data with different priorities, aiming at the performance deficiency of equal error protection LT(EEPLT) codes, propose the design of unequal error protection LT(UEPLT) codes with different weight priority. The proposed different weight priority UEPLT codes provide different protection level to data layer. The performance is judged by the decoding overhead and bit error rate(BER) of standard picture transmission. The results of simulation show that the UEPLT codes can recover most of high priority data with extremely low decoding overhead, and have a better bit error rate (BER) performance than the equal error protection (EEP) LT codes with a reasonable overhead. Further more, the performance of UEPLT codes with parabolic priority is better than the UEPLT codes with linear priority.