One of the important means by which 5G can be implemented is Ultra- Dense Multi – Tier( UDMT )future cellular network. For providing high data rate , low latency and better quality of servicein mobile communication system capacity must be high.It requires Spectralefficiency of the system should be high. Spectrum efficiency is a measure of how well the bandwidth resources are exploited in communication system . In this paper some analysis is done on spectrum efficiency of this system . It has been found that for high spectrum efficiency,Densification factor and Signal to Noise plus Interference ratio should be high. We have to choose correct value of Network load and channel bandwidth so that it can support required Spectrum efficiency.