Abstract: A toy block assembly puzzle, which is arranged diagonally, ideal for advanced users, comprises: a game tray (20) and plurality of assembly pieces (10) which will be arranged in a concave recess (21) of said game tray (20), characterized in that: said concave recess (21) of said game tray (20) including 50 concave slots (22), arranged in 11 rows; each odd row (row 1, 3, 5, 7, 9, 11) having 5 slots and each even row (row 2, 4, 6, 8, 10) having 4 slots; all slots (22) of said odd and even row are staggered arranged, forming 10 diagonal rows, each having an angle of 45 degree enclosed by said diagonal row and a border of said game tray (20); said assembly pieces (10) comprise 11 building blocks (1A˜1K), each having a different shape and formed by 3˜5 adjacent units; a total sum of units of said 11 building blocks (1A˜1K) are 50 units; said building blocks (1A˜1K) are placed diagonally with an oblique angle of 45 degree, into said 50 concave slots (22), which are provided on the game tray (20).