This paper analyzes the performance of IEEE 1451 networked smart sensors and then points out that its transmission bottleneck is its TII. According to the various practical techniques of TII, this paper analyzes the timing sequence and the data wire utilization ratio of TII protocol. It presents two practical methods in different applications, including the transmission mode of transferring 16 or 32 bits data after NACK transition and the method of increasing the cache size reasonably. The TII model is established in LabVIEW and used for simulating and testing the proposal methods. Results show that, compared with the ordinary TII model, the average data transmission rate of the transmission mode of transferring 16 or 32 bits data after NACK transition increases in 20.72% and 30.62%, while their delay-time decreases 23.64% and 35.41%. Using the method of increasing the cache size, the average data transmission rate increases, but the delay-time also increases.