Statistical model of dsDNA packaging to icosahedral bacteriophage capsid is presented. The model describes intraphage DNA as a globule, i.e. intramolecular liquid crystal. We analyse the free energy of DNA, which has a globulized part inside the phage capsid and coil-like tail outside it. Conditions when processes of DNA movement into capsid or back are thermodynamically favorable are investigated. These processes are not accompanied with any thermal effects. It is not "all or none" type process, i.e. intermediate stable states are possible. The role of DNA interaction with the capsid inner wall is considered. The essential model abilities for qualitative explanation of experimental data are exhibited.