In this papar, we calculated the influence of 5d-4f mixing caused by odd parity crystal field on level splitting of Ce3+ ions in CaF2 and SrF2 lattices. Results indicated that odd parity crystal field effect on level splitting may be fairly large. For lower levels in CaF2 the contribution of odd parity crystal field may amount to 15-30%. The order of 1st and 2nd excited states even reverses. On the other hand, it has been shown that configuration mixing is one of the possible mechanisms causing the extension of radial wave fanctions of ions in crystal.