i found that the fold change of different RNAseq expression analyse results  in edgeR is logFC, log2FC is also often used in other analysed ,i want to know if the logFC is same as log2FC in edgeR ,or it is based on exp(1).

Results reported by edgeR are always log2 so, yes, logFC is the same as log2FC in edgeR.

The use of base2 for log-fold-changes is usual practice in the bioinformatics literature and in most Bioconductor packages.

edgeR uses loge internally, but results are always converted to log2 for reporting.