Hollow stair of marking time of precast concrete

The utility model relates to a hollow stair of marking time of precast concrete, mark time including landing, prefabricated staircase board and the stair established on the prefabricated staircase board, landing includes landing and lower landing upward landing's one end is poured into a mould and is had upper crossbeam landing's one end is poured into a mould and is had lower floor's crossbeam down, the prefabricated staircase board is set up between upper crossbeam and lower floor's crossbeam, stair are marked time and are established on the prefabricated staircase board, still weigh sectionof thick bamboo core and node mounting including subtracting, subtracting a heavy section of thick bamboo core and transversely establishing in stair are marked time, all be equipped with 1 verticalhole for hoist on 4~6 sections stair at the every interval are marked time, it is fixed with the prefabricated staircase board that the vertical hole for hoist of stair on marking time is worn to establish by the reinforcing b