The advance of theory and techniques result in the emergence of various Brain Training Platforms. Based on researching results from psychology and cognitive neuron science, these platforms are helping their users to monitor and improve their brain capacities, and have received attentions and expectations from the public. By analyzing representative platforms and review related researches, we found that these platforms mostly use cognitive games adapted from classic cognitive paradigms to train users in a closed-loop manner. However, their validity and effective are found obscure. Basing on this analysis, we further discuss the design and development of future platforms.