It was predicted that the population of China will increase by 2〜3 hundred millions by the middle of next century, but the arable land will decrease by 18 million ha. This means that there will be a shortage of living space for 4〜5 hundred million populations, which will aggravate the situations of population, resources and environment. To expend living space is difficult duo to closing off afforested mountain for protection on upstream and recovering lakes from onec reclaimed farmland. However, the tidal flats along the coasts can provide a large amount of land resources. Historically, there were over 100 000 km² obtained from land progression and reclamation. In recent 50 years, China has acquired 11 000～12 000 km² new land with enhancing reclamation. This paper suggests making 10 000 — 15 000 km² living space for 20～30 millions population to get employment before the year 2050. The reclaimation to lower tidal flats is the key and difficult point in the next 50 years. According to the sediment shortage from sea or river between artificial landmaking and natural landmaking, the artificial impelling siltation and bio-impelling siltation engineerings are necessary to make up for sediment shortage of natural land-making. Besides, it is also necessary to improve environmental monitor and prediction precision and to piake innovations on engineering technology and so on.