Series development strategy is of great importance in wide-body aircraft engine design. To gain the insight into this domain, a number of wide-body aircraft engine performance designs based on a sequence of thrust requirements will be developed and studied in this paper. All design works are subject to one constraint which is remaining core engine unchanged or remaining entire engine unchanged. The result shows that once the baseline engine is defined, remaining entire engine unchanged with reduced rotating speed brings more benefits to deliver lower thrust level, while thrust growth would be readily obtained by re-matching low pressure system with the same core engine.