This article would like to first study the nature of laws governing Mainland fishermen entering Taiwan's sea area with fishing boats that employ them, and secondly discuss the legal responsibility of Mainland fishermen and carrier shipmasters when violating rules of approval, where judicial opinions and actual cases will be provided as examples to analyze potential criminal liabilities. Finally, with respect to security inspection issues like boat modification and overload that are related to using ”Floating Boat Houses” to accommodate Mainland fishermen, this article will analyze relevant laws, regulations, as well as powers and obligations of authorities concerned, and will present the author's personal opinions as reference for the use of future law amendment, in order to hopefully correct current deficiency and weakness in managing Mainland fishermen.