1. 女朋友家里从国内打了5万美元到我美国银行上 this is gift received from foreign person, less than 100K, no need to file anything 2. 然后我用casher's check把钱转给了她的银行 this is the gift you gave to your friend. It's over $14000, so you need to file gift tax form. Normally you won't need to pay any tax for this, but you need to submit the form.