同情！有类似经历。原因很多，建议上网或看vet.

可以google:why does my cat peed in the bed? little box 不仅要及时清理，还要按时清洗，可以用稀释的bleach,但是要清洗干净，不留任何气味。否则猫猫可能会不喜欢气味而不适用厕所。

床垫上一定要铺mattress protector. Here is a link but you need choose right size to fit your mattress.

http://www.amazon.com/gp/product/B002AQPUW0/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1

祝好运！