Employment pass application.

Hi guys, seriously need help for some advice. I was employed in a company (A) as accountant with an S pass. However after 1month I resign and join audit firm (B) with an E pass with salary of $2.2k (the ipa letter states 2.2k as well). Now I have a bigger offer from international firm with salary more than $3k with same position as B. As I have worked one month each in two company A & B. Will it affect my next E pass application? What if my in principle was rejected, can I continue my current employment with B as I have not resigned yet.

The minimum salary for an employment pass (EP) is S$3300/month.
Thus you will not get an EP, and I doubt you have one now (or was there a mis-typing in your post?).
MoM dislikes job-hoppers, and there are also various other reasons for your new application to be rejected (in which case you'll have to leave Singapore). This is the risk you take when changing job on a work pass in Singapore!

Does it mean that if new in principle was rejected, it will affect my current pass?. I'm audit associate. I think there is demand for the post that's why epass granted

If a new application is rejected while the old pass is still valid, you can continue working in the old job on the old pass.
However, the old employer can see in MoM's system that you applied for a new pass. It is common practise to lay-off such disloyal employees at the next possibility.
Mom also considers your unsuccessful attempts to change job and might not renew your current pass when it expires.