A novel rectangular shape microlens array having high sag for solid-state lighting is presented. Suggested microlens array which have high sag is realized using photoresist reflow and replication technique. Applying to the light-emitting-diode (LED) packaging, the rectangular shape of proposed microlens can maximize the fill factor of silicon based LED packaging and minimize the optical loss through the reduction of unnecessary reflection at the same time. Microlens, which has high sag, over 375 μm and large diameter, over 3 mm can enormously enhance output optical extraction efficiency. Moreover wafer level packaging technology is used to improve the aligning accuracy and mass production of LED packaging. This wafer level microlens array can be directly fabricated on LED packaging using replication method. It has many advantages in optical properties, low cost, high aligning accuracy, and mass production. Therefore wafer level LED packaging method adopts high sag rectangular microlens array demonstrates only improved optical performance but also mass production capability.