Is there any way to import parquet file to Dgraph database?
No, it isn’t possible. Dgraph supports RDF(in Dgraph’s format - simple NQuads) and JSON(Also with a custom format). Or you can use clients and send objects through there.
Its a manual option, but you could write a small Go app to read the parquet using e.g. github.com/xitongsys/parquet-go and then upload to Dgraph using the Dgraph Go client? I have done this myself with good results.