This article has researched on the new comparator design technical, including Four kinds of improving method. 1. A new energy-efficient ring oscillator collapse-based comparator named edge-pursuit comparator changes the comparison energy and adjusts the performance automatically without control, which decrease the unnecessary energy consumption. 2. A comparator with a dynamic bias pre-amplifier and compares it with current technologies in terms of energy consumption and input referred noise voltage. 3. A new type of low-power, high speed dynamic comparator, gm-enhanced, applies the separated gate-biasing cross-coupled transistors, the comparator becomes faster and have less consumption. 4.A floating reservoir capacitor called FIA is presented, which improves gm/ID to decreases the noise and reuses the current to achieve 7 times energy-efficiency improvement than the previous technology, SA latch. The cases above are studied step by step. Moreover, the rules and formular of the cases are derived to find their character, which will benefit to applying in the different requirement.