自己回答一下吧， 翻看了django1.7 bulk_create 的源碼， 上面有一段有意思的注釋：

# So this case is fun. When you bulk insert you don't get the primary
# keys back (if it's an autoincrement), so you can't insert into the
# child tables which references this. There are two workarounds, 1)
# this could be implemented if you didn't have an autoincrement pk,
# and 2) you could do it by doing O(n) normal inserts into the parent
# tables to get the primary keys back, and then doing a single bulk
# insert into the childmost table. Some databases might allow doing
# this by using RETURNING clause for the insert query. We're punting
# on these for now because they are relatively rare cases.

解決方法有兩種， 1）主鍵不設置為自增長，意思是需要自己指定主鍵的值嘍？沒理解錯吧
2）老老實實的一條條的插入吧

想了一下還是一條條插入，放到事務里面去操作. 不知道還有沒有更好的辦法