您需要使用位置 $ 更新操作符，用于从数组中删除元素.您需要这样做是因为节"是子文档的数组.

You need to use the positional $ update operator to remove the element from your array. You need this is because "sections" is an array of sub-documents.

db.test.findOneAndUpdate(
    { "sections._id" : ObjectId("56fea43a571332cc97e06d9e") }, 
    { "$pull": { "sections.$.registered": "e3d65a4e-2552-4995-ac5a-3c5180258d87" } } 
)