how to write this query for good performance ?

Question

I have query when i run it take may be 5 minutes to run

so i need to rewrite with good syntax for good performance

but i dont know how to enhance that query

select p.partid,p.maskedid,m.chemicalid into #temp2 from #temp t inner join parts p on ( p.maskedid=t.maskId and p.partid<>t.partId)
inner join chemicalmaster m on m.partid=p.partid and m.chemicalid<>t.chemicalId
update t1 set t1.status='conflict data' from #temp t1 inner join #temp2 t2 on  t1.maskid=t2.maskedid

 so how to enhancement this query please ?