The present study investigated the factors influencing the subject learning and explored the mechanism of teaching-learning of the learners with multi-cultural background. It also suggested a teaching-learning model to improve their learning capability. Factors influencing the achievement in a subject learning include socio-cultural knowledge, basic knowledge on the subject, thinking ability and communication ability. For the successful subject learning of the multi-cultural learners, each of the aforementioned factors should be in full work. Therefore, in KSL teaching-learning, a teaching-learning method needs to be applied that could prevent from any problems in the subject learning due to insufficiency of the four factors. Hardships of a multi-cultural learner encountered during subject learning could be overcome by providing communication ability, strategy, theme and vocabulary for the subject, when a multi-cultural learner learns a subject in Korean language.