Maintaining uniformity of software requirement documents with the artifacts of other phases of software lifecycle is very important. However, it is a difficult and time-consuming task. Natural language usually contains uncertainty. Most requirement documents were written in ambiguous natural language which is less formal and imprecise. Without proper modeling, the requirement knowledge is laboriously captured informally and thus the following integration with other artifacts is impracticable. In this paper, we propose a requirements modeling tool based on SysML. It assists users to confirm and improve the exactness of the requirements contents via the "Profile" of the requirements. Thereafter it will help the uniformity throughout the phases of software lifecycle.