I am trying to make an app Which can transfer some points to an RFID chip. RFID chip will store the data. Then an other iPhone with my app will receive the stored points wirelessly.
Is it possible to write some data in some RFID chip like (Mifare S50 chip) through my ios application and then read it back from a other iphone using my application? Please guide me with some reference or link.
If you only have an iPhone (without any RFID/NFC reader adapter), the answer is no. Current iPhones (we will see what features the iPhone 6 will bring us in that direction ...) do not have the necessary hardware to interact with MIFARE Classic chips (which -- in your case -- would be a 13.56 MHz iductive-coupling proximity reader with MIFARE Classic crypto support).
If your iPhone already has an NFC (or RFID) reader adapter, the answer depends on what specific adapter you use.
EDIT: As of today, this answer partially(!) applies to iPhone 6 (also see this question). The iPhone 6 has the necessary hardware to access such cards (i.e. an NFC controller chip from NXP), however there is no API that provides access to NFC reader/writer functionality. Moreover, there is doubts that the antenna boosting circuitry permits using the iPhone in reader/writer mode.