Abstract: The multi-touch technology has been widely used in various aspects of the every-day life, and has brought tremendous convenience during the process of the human-computer interaction. Among many new vision-based implementation methods for the multi-touch function, the frustrated total internal reflection (FTIR) method is one of the most promising one with unique advantages. However, the FTIR-based multi-touch implementation is sensitive to the ambient infrared noise and it currently can only be used in the dark environment. In this paper, a synchronized pulsed LED algorithm was proposed, namely SPLA, which could effectively improve the sensitivity of the FTIR-based multi-touch implementation in the normal ambient lighting environment. Based on the SPLA, a FTIR-based multi-touch platform was implemented . The experimental results show that the proposed SPLA increases the contrast of the blobs (touch points) by 3.5 times compared with the conventional methods. Because of similar hardware structure, the proposed SPLA can be also extended to minimize the ambient noise for other multi-touch implementation methods.