Sorry, I cannot type complicated Chinese on my computer. “体系”----- 整体的系统，从开始到结束需要经历的所有步骤 the whole system that you will encounter from the very beginning to the end “制度”----- 制定出来的规章制度，是人为设定的一些要求达到管理效果, the rules set up by managing group to manange e.g. 这个公司有上百年的历史，整个体系很合理高效，一些制度也很人性化。 ---- This company has a history of hundred years. System here is very reasonable and highly efficient. Some rules are also very humanized.

英文都为system, 这两个词的区别很微弱，很大一部分中国人都区别不开 In a word, 制度，通常是指社会制度 (social system); 体系，所涉及的范围更广 (general system)