美國CDMA手機沒有SIM卡，中國CDMA手機有 SIM卡。硬件不匹配。

至於GSM可用的前提有2個：

(1) Unlocked
(2) triband or quadband (Chinese and US GSM frequencies are different)

http://www.worldtimezone.com/gsm.html (3G for data only)

U S A

1900

850

3G 850/1900, 3G 1700/2100

Sprint 4G LTE; Sprint Clearwire WiMAX; MetroPCS 4G LTE; Verizon USA 4G; T-Mobile 4G; AT&T 4G (HSPA+ and LTE)

China	900				3G 2100
China, Hong Kong (SAR)	900	1800			3G 2100
China, Macau (SAR)	900	1800			3G 2100