By using the model of two similar equipments which have local same parts,Creat an index model for the assessment of the reliability,Then give a model parameter estimation method.

If its parameters of product size and performance and so on all have certain proportional relationship,the design will be done by using similar design theory.

Using similar design theory,the geometry sizes of the driven shafts in the reduction gearboxes were calculated;Throughing series components design table in SolidWorks,digitized fast design of the driven shafts series in the reduction gearboxes were finished.

By adopting a series of unique and advanced technologies,such as similar design,new high- temperature materials,sufficient tests,advanced LP casing module,the unit s cost-effectiveness,safety and reliability have reached the advanced level in the world.

The paper involves the technical features of the ultra supercritical 1000MW steam turbine made by HTC and TSB,By adopting similar design,new high-temperature materials,sufficient tests, advanced LP casing module and a series of particular and advanced technologies,The unit s cost-effectiveness and reliability have reached the advanced technology in the world.