USB Host and Ethernet shield simultaneously

Hello Everybody,
how I can use USB Host and Ethernet shield simultaneously. can anybody help me?thanks.

You are unspecific about which shields that you are using - not to mention which Arduino. For all that, about the worst thing you might be faced with is that both shields rely exclusively in the 6-pin ICSP cluster for the SPI bus, thereby obliging you to replace one socket with one that has extension pins.

Check the specifications.

I have never seen an Ethernet shield with wiring options, but the host shield should be configurable. If it isn't, get one that is.

i use ethernet shiled W5100 and MAX3421E-based USB Host Shield.if one of them,removed can work properly.

The first step is to find the circuit diagrams of the two shields so you can see if there are any pin conflicts. For example the pin used for 'chip select' (slave select or SS) can often be a problem.

i think both the shield use the ss/pin to change the pin ss to other pin for usb host shield?

Unplug the USB host shield and manually use jumper wires to connect the power, ground, MISO, MOSI and SCK. Connect SS to an unused pin and modify your code (or library) to use the new pin.

A pretty unreasonable question when you say nothing about the shield. I imagine they might ALL have a MAX3421E on them but, as mentioned above, the board should be configurable. Just in case you are lost with that word, it means that you should be able to wire SS to an alternative pin, thereby avoiding a clash. This may involve opening a solder bridge, or perhaps a jumper.