Abstract: Liquefied natural gas (LNG) has boomed recently to account for 30.5% of global natural gas trades in 2010. In some coastal cities in China, LNG has being introduced into pipeline systems. But natural gas quality specification has never been managed in a scientific way, and there are no detailed technical specification and reliable methods to predict interchangeability. The performances of 32 sampled gas cookers under 11 different gases were experimentally measured to explore interchangeability between LNG and pipeline natural gas. The results show that excessive CO emissions are likely to be caused by the introduction of LNG. Systematic researches are urgently essential to be carried out in the field of natural gas quality specification, in order to avoid expensive cost for conversions in future.