All scientists know well: to achieve nucleus fusion, a temperature of hundreds of millions of degrees is required. Only in this case, the kinetic energy of nucleus overcomes the repulsive electric force of nucleus and connects two initial nucleuses into a single nucleus. In the last sixty years, scientists have spent tens of billion US dollars attempting to develop useful thermonuclear fusion energy.Yet, today they still cannot reach a stable long-period thermonuclear reaction. They still are promising publically, after many years of effort, and additional tens of billions of US dollars to finally design the expensive but ultimately workable industrial installation, which possibly will produce electric energy more expensive than current heat, wind and hydro-electric stations can in 2015. Author, instead, uses well-known physical laws and shows the other andcheaperway: very low temperatures (0.01 ÷ 10K) and high-pressure (some thousands or millions of atmospheres) allows reaching the same results: thermonuclear fusion.He does not use kinetic energy of nucleus again repulsive force of nucleus, as in the long-touted conventional plasma confinement method. Instead, he uses the blocking the repulsive forces of nucleus by electrons (sphere Debya), very low-temperatureand high-pressure. In current time to reach these temperature and pressure are easily than hundreds millions degrees by magnetic or inertial confinement. New method for thermonuclear fusion is relatively cheap and allows use of other thermonuclear fuel which are less expensive and which produce theaneutronic reaction. Author offers new criterion for Ultra Cold Thermonuclear Fusion.