In this paper, a semi on-line version on m identical machines M1, M2, …,Mm(m≥3) was considered, where the processing time of the largest job is known in advance. Our goal is to maximize the minimum machine load, an NPLS algorithm was presented and its worst-case ratio was proved to be equal to m-1 which is the best possible value. It is concluded that if the total processing time of jobs is also known to be greater than (2m-1)pmax where pmax is the largest jobs processing time, then the worst-case ratio is 2-1/m.