藍盒子是一座非典型的實驗型中劇場,和大劇院同樣位在4F、左右相對的位置。這個最多可到800人席位的多形式劇場，特色在於其可變的舞台位置和可調整深度、高度、位置的活動座椅，可滿足環形、三面、雙面、鏡框以及空場等多種觀眾席配置覆蓋全區的技術網架天花構造滿足多變的舞台配置需求,上方皆可架設燈光、佈景或所需設備。環繞全場的活動牆面，可在平面上搭配演出空間,設定入場動線開口和舞台背牆位置,其展開後一面吸音一面反音的材料也可用來調整不同表演所需的聲音環境效果。

藍盒子的藍有別於球劇場、大劇院,是更為深邃的Pantone 648C深藍，顛覆「黑盒子劇場一定要黑色」的既定印象，在入場時提供觀眾沉浸而不壓迫的空間，而當表演開始燈光關掉時，深藍色的吸光效果形成比黑色還深沉的背景,以突出表演效果。

The Blue Box is an atypical experimental theater, located opposite the Grand Theater and on the same level. The 800-seat multiform theater supports different stage configurations. The seating is flexible, and can be adjusted in terms of depth, height, and location for the thrust stage, the freeform stage, or the two-sided stage. The technical grid supports the lighting,scenography, and other facility settings for different stage configurations. The movable walls allow the audience circulation routes to be adapted for different performances. One side of the walls is sound absorbent, and the other side is sound reflective, creating different acoustic environments.

The interior of Blue Box is a deep Pantone 648C blue, subverting the convention that a black box must be black in color. The color creates an immersive, yet not oppressive space. When the lights are turned off before a performance, the light absorbent blue color forms an even darker background to highlight the start of the performance.