Species, varieties and area of Bt (Bacillus thuringiensis) transgenic crops have increased rapidly worldwide in the past 11 years (1996-2006) for economic, environmental and health benefits.  However, the ecological risks of Bt transgenic crops were critically highlighted for potential adverse effects on agroecosystems, in particular, non-target effects on soil microorganisms.  Arbuscular mycorrhizal fungi (AMF) are important soil microorganisms providing a range of benefits to the majority of crop plants in the agroecosystem, worthy of monitoring for non-target effects of Bt transgenic crops.  Bt transgenic crops may affect AMF in many ways during their life with regard to the temporal-spatial relevance between the occurrence of Bt proteins and fungal symbiotic development of AMF.  This may lead to an unwelcome surprise with regard to specific abundance and diversity of AMF when Bt transgenic crops are planted continuously.  It is concluded that interactions between AMF and Bt transgenic crops at individual and community level are a new urgent soil ecological issue.  Some evidence about Bt transgenic crop effects on AMF revealed by recent articles are summarized, and research prospects are highlighted in the paper.