The　heavy　metal　ions　pollution　aggravates　the　clean　water　shortage　crisis.　The　polyamide　nanofiltration　membranes　fabricated　via　interfacial　polymerization　are　potential　for　removal　of　heavy　metal　ions,　but　their　negatively　charge　surface　renders　low　rejection　efficiency.　To　solve　the　issue,　we　proposed　a　surface　charge　conversion　method　by　chemical　crosslinking　the　positively　charged　polyethyleneimine　(PEI)　on　the　thin　polyamide　nanofiltration　membrane.　The　such　prepared　positively　charged　nanofiltration　membrane　presents　enhanced　rejection　to　heavy　metal　ions　while　maintaining　the　high　water　permeance.　After　optimization　of　the　membrane　fabrication　conditions,　the　PEI-modified　membrane　demonstrates　a　pure　water　permeance　of　7　center　dot　2　L　center　dot　m(-2)center　dot　h(-1　center　dot)bar(-1)　with　＞95　%　rejection　to　Cu2+　and　other　heavy　metal　ions.　Moreover,　the　membrane　could　maintain　the　high　performance　to　mixed　metal　ion　aqueous　solutions.　Combined　with　its　remarkable　stability　under　high　pressure　and　long-term　running,　the　positively　charged　membrane　has　great　potential　to　be　deployed　for　treatment　of　practical　wastewater　towards　sustainable　development　via　cleaning　water　and　precious　metals　recovery.